Eventually I will run out of cute ways to use SAS software to create and visualize a Christmas-themed image.
But not this year!

My recent article about how to create Pascal's matrix in SAS included a lower triangular matrix that exhibits self-similar patterns. If you take the Pascal matrix modulo 9 and reflect it across the Y axis, you get a triangular array that looks a little bit like a Christmas tree. You can add a "trunk" to the bottom of the tree to improve the resemblance. As shown in my previous post, you can use a heat map to visualize the matrix. In the following SAS/IML program, I use a green palette of colors to visualize the Pascal triangle values modulo 9. The resulting heat map is shown at the top of this article.

About Author

Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of PROC IML and SAS/IML Studio. His areas of expertise include computational statistics, simulation, statistical graphics, and modern methods in statistical data analysis. Rick is author of the books Statistical Programming with SAS/IML Software and Simulating Data with SAS.